RNAi knockdown of CAPAr gene affects survival and fecundity of Bemisia tabaci (Gennadius)

Abstract

Graphical abstract representing the functioning of CAPA receptor in Bemisia tabaci diuresis process and silencing of CAPAr resulting into inactivation of diuresis. • CAPAr gene silencing resulted into significant whitefly mortality. • Reduced fecundity and survival of CAPAr knockdown whiteflies. • Reduced relative gene expression of CAPAr in dsRNA fed whiteflies. Bemisia tabaci (Gennadius) Asia II 1 cause significant economic losses to cotton crop, directly by feeding on sap and indirectly through virus transmission. Although the current control methods are the combination of different tactics but still the chemical control is heavily relied. B. tabaci has gained resistance to majority of the insecticides which has made it difficult to manage this pest using synthetic chemicals. RNAi based gene silencing has been evolved as potential biochemical tool for specific gene silencing of target insect-pest and has been successfully demonstrated for Hemipteran insects. Here, we report the successful silencing of the CAPAr gene in B. tabaci which encodes for the G-protein coupled receptor (a transmembrane membrane peptide). Silencing of CAPAr gene resulted into reduced survival and fecundity of B. tabaci . Oral delivery of dsRNA mediated artificial diet corresponding to CAPAr gene resulted into significantly high adult mortality of 30.74% in treatment dsCAPAr 1.0 µg/µl after 48 hr of dsRNA feeding. A significant reduction in whitefly female fecundity was recorded for all the dsCAPAr concentrations with lowest value of 53.51 eggs per female in dsCAPAr 1.0 µg/µl. The relative gene expression of CAPAr gene further confirms the down regulation of CAPAr gene in knock down adult whiteflies. Our investigation proves the importance of CAPAr for B. tabaci survival and may be exploited as potential tool which can be strategic in integrated management programme for B. tabaci .